Turbine engines are used as the primary power source for various kinds of aircraft. The engines may also serve as auxiliary power sources that drive air compressors, hydraulic pumps, and industrial electrical power generators. Most turbine engines generally follow the same basic power generation procedure. Compressed air is mixed with fuel and burned, and the expanding hot combustion gases are directed against stationary turbine vanes in the engine. The vanes turn the high velocity gas flow partially sideways to impinge onto turbine blades mounted on a rotatable turbine disk. The force of the impinging gas causes the turbine disk to spin at high speed. Jet propulsion engines use the power created by the rotating turbine disk to draw more air into the engine, and the high velocity combustion gas is passed out of the gas turbine aft end to create forward thrust.
Turbine engines typically operate more efficiently with increasingly hotter operating temperatures. Accordingly, to maximize the engine efficiency, attempts have been made to form turbine engine components having higher operating temperature capabilities. For example, turbine disks are typically made of nickel-based superalloys or cobalt-based superalloys, which exhibit strength and creep resistance at relatively high temperatures (e.g., 704° C. (1300° F.)), as well as resistance to fatigue crack initiation. However, as turbine disks are increasingly being exposed to operating temperatures above 704° C. (1300° F.), the aforementioned superalloys from which they are fabricated may not be adequately corrosion-resistant in such environments. In particular, the superalloys may be susceptible to salt attacks, which may decrease the useful life of the turbine disk.
Hence, there is a need for materials and components that may be more corrosion-resistant when exposed to engine operating temperatures that exceed 704° C. (1300° F.). In addition it is desirable for materials to be relatively inexpensive to implement into turbine engine component manufacturing processes. Moreover, it is desirable for the manufacturing process to be relatively simple to perform.